This invention is related to a kind of alloy material used for hard surfacing, more particularly, this invention is related to a type of alloy material comprised mainly of C, Si, Cr, W and Cu elements and is a type of low C, high Cr, high Si, high W and Cu wear resistant Co-substitute Ni-base alloy for hard surfacing.
Among the existing Co-substitute wear alloys, the Ni-base alloy is mostly used, in which the low boron low carbon group according to the different content of the strengthening elements, Cr, W, Si, can be divided into a high Cr, low Si type (Cr.gtoreq.20%, Si&lt;4.5%, U.S. Pat. No. 4,515,869) and a low Cr high Si type (Cr&lt;20%, Si.gtoreq.4.5%, Japanese Patent SHOWA 55-31127) and a high Cr, high Si and low W type (Cr&gt;20%, Si&gt;4.5%, W.ltoreq.5% U.S. Pat. No. 4,404,049; Japanese Patent SHOWA 57-16495) etc. in the determination of the chemical composition of the existing Co-substitute alloys, the effects of the changes of individual elements on the properties of the alloy are usually investigated, but the effects of the combination of elements as a whole and the changes of their contents are seldom investigated and studied, so that only one or some of the properties of the existing Ni-base alloys can be the same to those of the Co-base alloy.
The microstructures of the above-mentioned Ni-base alloys basically stimulates the structural morphology of the Co-base Stellite No 6 alloy, that is either eutectic (binary or trinary eutectic formed by carbide, boride or silicate and solid solution) or dispersion carbide is added to solid solution strengthened Ni solid solution matrix. With this kind of structural morphology the solid solution and the strengthened eutectic phase will often at elevated temperature and the dispersion carbide can not prevent the matrix from plastic deformation caused by wear at elevated temperature, so that the ideal adhesive wear resistance at elevated temperature could not be developed as in the existing Co-substitute alloys or the original Co-base Stellite No 6 alloy. In addition, because the strengthened eutectic phase formed a continuous network lattice over the solid solution grain boundaries, the ductility, toughness and intercrystalline corrosion resistance of the material decreased.